A previously developed perfused lung system has been used to examine the dynamic interaction between the lung and several basic amines. Of the basic amines which have been studied in detail, i.e., imipramine, methadone, and amphetamine, only the latter failed to persist and had a transport system (probably the noradrenoline transport system) involved in its removal. The persistence aspect of basic amine interaction with lung tissue is now also being pursued in both whole animal studies. In addition, physiological models for describing the dynamic interaction of these compounds with lung tissue are being developed. The removal and modification of 5-HT and the prostaglandins from the circulation by the lung has also been studied in detail. From this investigation the existence of a transport system in lung tissue for the removal of some prostaglandins has been established. Examination of the effects that other chemicals which accumulate in the lung have on these inactivation systems as well as the effects of exposure to various environmental pollutants (O3, NO2, SO2, etc.) is being pursued.